I did some googling and here's my answer
.mirror {
display: block;
-moz-transform: matrix(-1, 0, 0, 1, 0, 0);
-webkit-transform: matrix(-1, 0, 0, 1, 0, 0);
-o-transform: matrix(-1, 0, 0, 1, 0, 0);
}
<!--[if IE]>
<style>
.mirror {
filter: progid:DXImageTransform.Microsoft.BasicImage(mirror=1);
}
</style>
<![endif]-->
<div class="mirror">testing</div>
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